genbench.py

import sys
import time

sys.setrecursionlimit(1200)

def g1(depth):
    if depth > 0:
        it = g1(depth-1)
        yield next(it)
    else:
        yield 42

def g2(depth):
    if depth > 0:
        it = g2(depth-1)
        try:
            yield next(it)
        except StopIteration:
            pass
    else:
        yield 42

def timeit(gen, depth, repeat):
    t0 = time.time()
    for _ in range(repeat):
        assert list(gen(depth)) == [42]
    t1 = time.time()
    print('%s(%d) * %d: total %.3f, per call %.6f, per frame %.9f' %
          (gen.__name__, depth, repeat, t1-t0, (t1-t0)/repeat, (t1-t0)/repeat/depth))

# Note alternating between g1 and g2.
timeit(g1, 1000, 1000)
timeit(g2, 1000, 1000)
timeit(g1, 1000, 1000)
timeit(g2, 1000, 1000)
timeit(g1, 1000, 1000)
timeit(g2, 1000, 1000)

output

python3.4 genbench.py 
g1(1000) * 1000: total 0.660, per call 0.000660, per frame 0.000000660
g2(1000) * 1000: total 0.848, per call 0.000848, per frame 0.000000848
g1(1000) * 1000: total 0.660, per call 0.000660, per frame 0.000000660
g2(1000) * 1000: total 0.865, per call 0.000865, per frame 0.000000865
g1(1000) * 1000: total 0.706, per call 0.000706, per frame 0.000000706
g2(1000) * 1000: total 0.895, per call 0.000895, per frame 0.000000895

python3.5 genbench.py 
g1(1000) * 1000: total 0.727, per call 0.000727, per frame 0.000000727
g2(1000) * 1000: total 0.917, per call 0.000917, per frame 0.000000917
g1(1000) * 1000: total 0.730, per call 0.000730, per frame 0.000000730
g2(1000) * 1000: total 0.870, per call 0.000870, per frame 0.000000870
g1(1000) * 1000: total 0.690, per call 0.000690, per frame 0.000000690
g2(1000) * 1000: total 0.908, per call 0.000908, per frame 0.000000908

# This is with Chris A's patch.
./python.exe genbench.py 
g1(1000) * 1000: total 0.697, per call 0.000697, per frame 0.000000697
g2(1000) * 1000: total 0.895, per call 0.000895, per frame 0.000000895
g1(1000) * 1000: total 0.685, per call 0.000685, per frame 0.000000685
g2(1000) * 1000: total 0.862, per call 0.000862, per frame 0.000000862
g1(1000) * 1000: total 0.681, per call 0.000681, per frame 0.000000681
g2(1000) * 1000: total 0.898, per call 0.000898, per frame 0.000000898